1
|
de Smit SM, van Mameren TD, van Zwet K, van Veelen HPJ, Cristina Gagliano M, Strik DPBTB, Bitter JH. Integration of biocompatible hydrogen evolution catalyst developed from metal-mix solutions with microbial electrosynthesis. Bioelectrochemistry 2024; 158:108724. [PMID: 38714063 DOI: 10.1016/j.bioelechem.2024.108724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 04/29/2024] [Accepted: 05/01/2024] [Indexed: 05/09/2024]
Abstract
Microbial conversion of CO2 to multi-carbon compounds such as acetate and butyrate is a promising valorisation technique. For those reactions, the electrochemical supply of hydrogen to the biocatalyst is a viable approach. Earlier we have shown that trace metals from microbial growth media spontaneously form in situ electro-catalysts for hydrogen evolution. Here, we show biocompatibility with the successful integration of such metal mix-based HER catalyst for immediate start-up of microbial acetogenesis (CO2 to acetate). Also, n-butyrate formation started fast (after twenty days). Hydrogen was always produced in excess, although productivity decreased over the 36 to 50 days, possibly due to metal leaching from the cathode. The HER catalyst boosted microbial productivity in a two-step microbial community bioprocess: acetogenesis by a BRH-c20a strain and acetate elongation to n-butyrate by Clostridium sensu stricto 12 (related) species. These findings provide new routes to integrate electro-catalysts and micro-organisms showing respectively bio and electrochemical compatibility.
Collapse
Affiliation(s)
- Sanne M de Smit
- Environmental Technology, Wageningen University and Research, Wageningen, The Netherlands; Biobased Chemistry and Technology, Wageningen University and Research, Wageningen, The Netherlands
| | - Thomas D van Mameren
- Environmental Technology, Wageningen University and Research, Wageningen, The Netherlands
| | - Koen van Zwet
- Environmental Technology, Wageningen University and Research, Wageningen, The Netherlands
| | - H Pieter J van Veelen
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Leeuwarden, The Netherlands
| | - M Cristina Gagliano
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Leeuwarden, The Netherlands
| | - David P B T B Strik
- Environmental Technology, Wageningen University and Research, Wageningen, The Netherlands.
| | - Johannes H Bitter
- Biobased Chemistry and Technology, Wageningen University and Research, Wageningen, The Netherlands.
| |
Collapse
|
2
|
Zhai Y, Tong S, Chen L, Zhang Y, Amin FR, Khalid H, Liu F, Duan Y, Chen W, Chen G, Li D. The enhancement of energy supply in syngas-fermenting microorganisms. ENVIRONMENTAL RESEARCH 2024; 252:118813. [PMID: 38574985 DOI: 10.1016/j.envres.2024.118813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 03/25/2024] [Accepted: 03/26/2024] [Indexed: 04/06/2024]
Abstract
After the second industrial revolution, social productivity developed rapidly, and the use of fossil fuels such as coal, oil, and natural gas increased greatly in industrial production. The burning of these fossil fuels releases large amounts of greenhouse gases such as CO2, which has caused greenhouse effects and global warming. This has endangered the planet's ecological balance and brought many species, including animals and plants, to the brink of extinction. Thus, it is crucial to address this problem urgently. One potential solution is the use of syngas fermentation with microbial cell factories. This process can produce chemicals beneficial to humans, such as ethanol as a fuel while consuming large quantities of harmful gases, CO and CO2. However, syngas-fermenting microorganisms often face a metabolic energy deficit, resulting in slow cell growth, metabolic disorders, and low product yields. This problem limits the large-scale industrial application of engineered microorganisms. Therefore, it is imperative to address the energy barriers of these microorganisms. This paper provides an overview of the current research progress in addressing energy barriers in bacteria, including the efficient capture of external energy and the regulation of internal energy metabolic flow. Capturing external energy involves summarizing studies on overexpressing natural photosystems and constructing semiartificial photosynthesis systems using photocatalysts. The regulation of internal energy metabolic flows involves two parts: regulating enzymes and metabolic pathways. Finally, the article discusses current challenges and future perspectives, with a focus on achieving both sustainability and profitability in an economical and energy-efficient manner. These advancements can provide a necessary force for the large-scale industrial application of syngas fermentation microbial cell factories.
Collapse
Affiliation(s)
- Yida Zhai
- School of Marine Science and Technology, Harbin Institute of Technology (Weihai), Weihai, 264209, PR China; School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China; Tianjin Key Laboratory for Industrial Biological System and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, PR China
| | - Sheng Tong
- Tianjin Key Laboratory for Industrial Biological System and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, PR China
| | - Limei Chen
- Tianjin Key Laboratory for Industrial Biological System and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, PR China
| | - Yuan Zhang
- Tianjin Key Laboratory for Industrial Biological System and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, PR China
| | - Farrukh Raza Amin
- Tianjin Key Laboratory for Industrial Biological System and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, PR China
| | - Habiba Khalid
- Tianjin Key Laboratory for Industrial Biological System and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, PR China
| | - Fuguo Liu
- School of Marine Science and Technology, Harbin Institute of Technology (Weihai), Weihai, 264209, PR China; School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Yu Duan
- School of Marine Science and Technology, Harbin Institute of Technology (Weihai), Weihai, 264209, PR China; School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China; Tianjin Key Laboratory for Industrial Biological System and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, PR China
| | - Wuxi Chen
- Tianjin Key Laboratory for Industrial Biological System and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, PR China
| | - Guofu Chen
- School of Marine Science and Technology, Harbin Institute of Technology (Weihai), Weihai, 264209, PR China.
| | - Demao Li
- Tianjin Key Laboratory for Industrial Biological System and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, PR China.
| |
Collapse
|
3
|
Schwarz I, Angelina A, Hambrock P, Weuster-Botz D. Simultaneous Formate and Syngas Conversion Boosts Growth and Product Formation by Clostridium ragsdalei. Molecules 2024; 29:2661. [PMID: 38893534 PMCID: PMC11174074 DOI: 10.3390/molecules29112661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 05/28/2024] [Accepted: 05/31/2024] [Indexed: 06/21/2024] Open
Abstract
Electrocatalytic CO2 reduction to CO and formate can be coupled to gas fermentation with anaerobic microorganisms. In combination with a competing hydrogen evolution reaction in the cathode in aqueous medium, the in situ, electrocatalytic produced syngas components can be converted by an acetogenic bacterium, such as Clostridium ragsdalei, into acetate, ethanol, and 2,3-butanediol. In order to study the simultaneous conversion of CO, CO2, and formate together with H2 with C. ragsdalei, fed-batch processes were conducted with continuous gassing using a fully controlled stirred tank bioreactor. Formate was added continuously, and various initial CO partial pressures (pCO0) were applied. C. ragsdalei utilized CO as the favored substrate for growth and product formation, but below a partial pressure of 30 mbar CO in the bioreactor, a simultaneous CO2/H2 conversion was observed. Formate supplementation enabled 20-50% higher growth rates independent of the partial pressure of CO and improved the acetate and 2,3-butanediol production. Finally, the reaction conditions were identified, allowing the parallel CO, CO2, formate, and H2 consumption with C. ragsdalei at a limiting CO partial pressure below 30 mbar, pH 5.5, n = 1200 min-1, and T = 32 °C. Thus, improved carbon and electron conversion is possible to establish efficient and sustainable processes with acetogenic bacteria, as shown in the example of C. ragsdalei.
Collapse
Affiliation(s)
| | | | | | - Dirk Weuster-Botz
- Chair of Biochemical Engineering, School of Engineering and Design, Technical University of Munich, Boltzmannstr. 15, 85748 Garching, Germany; (I.S.)
| |
Collapse
|
4
|
Allaart MT, Korkontzelos C, Sousa DZ, Kleerebezem R. A novel experimental method to determine substrate uptake kinetics of gaseous substrates applied to the carbon monoxide-fermenting Clostridium autoethanogenum. Biotechnol Bioeng 2024; 121:1325-1335. [PMID: 38265153 DOI: 10.1002/bit.28652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 12/20/2023] [Accepted: 12/22/2023] [Indexed: 01/25/2024]
Abstract
Syngas fermentation has gained momentum over the last decades. The cost-efficient design of industrial-scale bioprocesses is highly dependent on quantitative microbial growth data. Kinetic and stoichiometric models for syngas-converting microbes exist, but accurate experimental validation of the derived parameters is lacking. Here, we describe a novel experimental approach for measuring substrate uptake kinetics of gas-fermenting microbes using the model microorganism Clostridium autoethanogenum. One-hour disturbances of a steady-state chemostat bioreactor with increased CO partial pressures (up to 1.2 bar) allowed for measurement of biomass-specific CO uptake- and CO2 production rates (q CO ${q}_{{CO}}$ ,q CO 2 ${q}_{{{CO}}_{2}}$ ) using off-gas analysis. At a pCO of 1.2 bar, aq CO ${q}_{{CO}}$ of -119 ± 1 mmol g-1 X h-1 was measured. This value is 1.8-3.5-fold higher than previously reported experimental and kinetic modeling results for syngas fermenters. Analysis of the catabolic flux distribution reveals a metabolic shift towards ethanol production at the expense of acetate at pCO ≥ $\ge $ 0.6 atm, likely to be mediated by acetate availability and cellular redox state. We characterized this metabolic shift as acetogenic overflow metabolism. These results provide key mechanistic understanding of the factors steering the product spectrum of CO fermentation in C. autoethanogenum and emphasize the importance of dedicated experimental validation of kinetic parameters.
Collapse
Affiliation(s)
| | | | - Diana Z Sousa
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| |
Collapse
|
5
|
Heffernan J, Garcia Gonzalez RA, Mahamkali V, McCubbin T, Daygon D, Liu L, Palfreyman R, Harris A, Koepke M, Valgepea K, Nielsen LK, Marcellin E. Adaptive laboratory evolution of Clostridium autoethanogenum to metabolize CO 2 and H 2 enhances growth rates in chemostat and unravels proteome and metabolome alterations. Microb Biotechnol 2024; 17:e14452. [PMID: 38568755 PMCID: PMC10990044 DOI: 10.1111/1751-7915.14452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 03/03/2024] [Accepted: 03/06/2024] [Indexed: 04/05/2024] Open
Abstract
Gas fermentation of CO2 and H2 is an attractive means to sustainably produce fuels and chemicals. Clostridium autoethanogenum is a model organism for industrial CO to ethanol and presents an opportunity for CO2-to-ethanol processes. As we have previously characterized its CO2/H2 chemostat growth, here we use adaptive laboratory evolution (ALE) with the aim of improving growth with CO2/H2. Seven ALE lineages were generated, all with improved specific growth rates. ALE conducted in the presence of 2% CO along with CO2/H2 generated Evolved lineage D, which showed the highest ethanol titres amongst all the ALE lineages during the fermentation of CO2/H2. Chemostat comparison against the parental strain shows no change in acetate or ethanol production, while Evolved D could achieve a higher maximum dilution rate. Multi-omics analyses at steady state revealed that Evolved D has widespread proteome and intracellular metabolome changes. However, the uptake and production rates and titres remain unaltered until investigating their maximum dilution rate. Yet, we provide numerous insights into CO2/H2 metabolism via these multi-omics data and link these results to mutations, suggesting novel targets for metabolic engineering in this bacterium.
Collapse
Affiliation(s)
- James Heffernan
- Australian Institute of Bioengineering and NanotechnologyThe University of QueenslandSt. LuciaQueenslandAustralia
- ARC Centre of Excellence in Synthetic BiologyThe University of QueenslandSt. LuciaQueenslandAustralia
| | - R. Axayactl Garcia Gonzalez
- Australian Institute of Bioengineering and NanotechnologyThe University of QueenslandSt. LuciaQueenslandAustralia
- ARC Centre of Excellence in Synthetic BiologyThe University of QueenslandSt. LuciaQueenslandAustralia
| | | | - Tim McCubbin
- Queensland Metabolomics and Proteomics Q‐MAPThe University of QueenslandSt. LuciaQueenslandAustralia
| | - Dara Daygon
- Queensland Metabolomics and Proteomics Q‐MAPThe University of QueenslandSt. LuciaQueenslandAustralia
| | - Lian Liu
- Queensland Metabolomics and Proteomics Q‐MAPThe University of QueenslandSt. LuciaQueenslandAustralia
| | - Robin Palfreyman
- Queensland Metabolomics and Proteomics Q‐MAPThe University of QueenslandSt. LuciaQueenslandAustralia
| | | | | | - Kaspar Valgepea
- ERA Chair in Gas Fermentation Technologies, Institute of TechnologyUniversity of TartuTartuEstonia
| | - Lars Keld Nielsen
- Australian Institute of Bioengineering and NanotechnologyThe University of QueenslandSt. LuciaQueenslandAustralia
- ARC Centre of Excellence in Synthetic BiologyThe University of QueenslandSt. LuciaQueenslandAustralia
- Queensland Metabolomics and Proteomics Q‐MAPThe University of QueenslandSt. LuciaQueenslandAustralia
- The Novo Nordisk Foundation Center for BiosustainabilityTechnical University of DenmarkKgs. LyngbyDenmark
| | - Esteban Marcellin
- Australian Institute of Bioengineering and NanotechnologyThe University of QueenslandSt. LuciaQueenslandAustralia
- ARC Centre of Excellence in Synthetic BiologyThe University of QueenslandSt. LuciaQueenslandAustralia
- Queensland Metabolomics and Proteomics Q‐MAPThe University of QueenslandSt. LuciaQueenslandAustralia
| |
Collapse
|
6
|
Noori MT, Rossi R, Logan BE, Min B. Hydrogen production in microbial electrolysis cells with biocathodes. Trends Biotechnol 2024:S0167-7799(23)00366-9. [PMID: 38360421 DOI: 10.1016/j.tibtech.2023.12.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 12/17/2023] [Accepted: 12/29/2023] [Indexed: 02/17/2024]
Abstract
Electroautotrophic microbes at biocathodes in microbial electrolysis cells (MECs) can catalyze the hydrogen evolution reaction with low energy demand, facilitating long-term stable performance through specific and renewable biocatalysts. However, MECs have not yet reached commercialization due to a lack of understanding of the optimal microbial strains and reactor configurations for achieving high performance. Here, we critically analyze the criteria for the inocula selection, with a focus on the effect of hydrogenase activity and microbe-electrode interactions. We also evaluate the impact of the reactor design and key parameters, such as membrane type, composition, and electrode surface area on internal resistance, mass transport, and pH imbalances within MECs. This analysis paves the way for advancements that could propel biocathode-assisted MECs toward scalable hydrogen gas production.
Collapse
Affiliation(s)
- Md Tabish Noori
- Department of Environmental Science and Engineering, Kyung Hee University - Global Campus, Yongin-Si, South Korea
| | - Ruggero Rossi
- Department of Environmental Health and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Bruce E Logan
- Department of Civil and Environmental Engineering, Penn State University, Pennsylvania, PA 16801, USA
| | - Booki Min
- Department of Environmental Science and Engineering, Kyung Hee University - Global Campus, Yongin-Si, South Korea.
| |
Collapse
|
7
|
Flaiz M, Poehlein A, Wilhelm W, Mook A, Daniel R, Dürre P, Bengelsdorf FR. Refining and illuminating acetogenic Eubacterium strains for reclassification and metabolic engineering. Microb Cell Fact 2024; 23:24. [PMID: 38233843 PMCID: PMC10795377 DOI: 10.1186/s12934-024-02301-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 01/09/2024] [Indexed: 01/19/2024] Open
Abstract
BACKGROUND The genus Eubacterium is quite diverse and includes several acetogenic strains capable of fermenting C1-substrates into valuable products. Especially, Eubacterium limosum and closely related strains attract attention not only for their capability to ferment C1 gases and liquids, but also due to their ability to produce butyrate. Apart from its well-elucidated metabolism, E. limosum is also genetically accessible, which makes it an interesting candidate to be an industrial biocatalyst. RESULTS In this study, we examined genomic, phylogenetic, and physiologic features of E. limosum and the closest related species E. callanderi as well as E. maltosivorans. We sequenced the genomes of the six Eubacterium strains 'FD' (DSM 3662T), 'Marburg' (DSM 3468), '2A' (DSM 2593), '11A' (DSM 2594), 'G14' (DSM 107592), and '32' (DSM 20517) and subsequently compared these with previously available genomes of the E. limosum type strain (DSM 20543T) as well as the strains 'B2', 'KIST612', 'YI' (DSM 105863T), and 'SA11'. This comparison revealed a close relationship between all eleven Eubacterium strains, forming three distinct clades: E. limosum, E. callanderi, and E. maltosivorans. Moreover, we identified the gene clusters responsible for methanol utilization as well as genes mediating chain elongation in all analyzed strains. Subsequent growth experiments revealed that strains of all three clades can convert methanol and produce acetate, butyrate, and hexanoate via reverse β-oxidation. Additionally, we used a harmonized electroporation protocol and successfully transformed eight of these Eubacterium strains to enable recombinant plasmid-based expression of the gene encoding the fluorescence-activating and absorption shifting tag (FAST). Engineered Eubacterium strains were verified regarding their FAST-mediated fluorescence at a single-cell level using a flow cytometry approach. Eventually, strains 'FD' (DSM 3662T), '2A' (DSM 2593), '11A' (DSM 2594), and '32' (DSM 20517) were genetically engineered for the first time. CONCLUSION Strains of E. limosum, E. callanderi, and E. maltosivorans are outstanding candidates as biocatalysts for anaerobic C1-substrate conversion into valuable biocommodities. A large variety of strains is genetically accessible using a harmonized electroporation protocol, and FAST can serve as a reliable fluorescent reporter protein to characterize genetically engineered cells. In total eleven strains have been assigned to distinct clades, providing a clear and updated classification. Thus, the description of respective Eubacterium species has been emended, improved, aligned, and is requested to be implemented in respective databases.
Collapse
Affiliation(s)
- Maximilian Flaiz
- Laboratory of Microbiology, Wageningen University and Research, Wageningen, The Netherlands.
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany.
| | - Anja Poehlein
- Genomic and Applied Microbiology & Göttingen Genomics Laboratory, Georg-August University, Göttingen, Germany
| | - Wiebke Wilhelm
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
| | - Alexander Mook
- Institute of Molecular Biology and Biotechnology of Prokaryotes, University of Ulm, Ulm, Germany
| | - Rolf Daniel
- Genomic and Applied Microbiology & Göttingen Genomics Laboratory, Georg-August University, Göttingen, Germany
| | - Peter Dürre
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
| | - Frank R Bengelsdorf
- Institute of Molecular Biology and Biotechnology of Prokaryotes, University of Ulm, Ulm, Germany.
| |
Collapse
|
8
|
Antonicelli G, Ricci L, Tarraran L, Fraterrigo Garofalo S, Re A, Vasile NS, Verga F, Pirri CF, Menin B, Agostino V. Expanding the product portfolio of carbon dioxide and hydrogen-based gas fermentation with an evolved strain of Clostridium carboxidivorans. BIORESOURCE TECHNOLOGY 2023; 387:129689. [PMID: 37597573 DOI: 10.1016/j.biortech.2023.129689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 08/09/2023] [Accepted: 08/15/2023] [Indexed: 08/21/2023]
Abstract
CO2:H2-based gas fermentation with acetogenic Clostridium species are at an early stage of development. This work exploited the Adaptive Laboratory Evolution technique to improve the growth of C. carboxidivorans P7 on CO2 and H2. An adapted strain with decreased growth lag phase and improved biomass production was obtained. Genomic analysis revealed a conserved frameshift mutation in the catalytic subunit of the hexameric hydrogenase gene. The resulted truncated protein variant, most likely lacking its functionality, suggests that other hydrogenases might be more efficient for H2-based growth of this strain. Furthermore, the adapted strain generated hexanol as primary fermentation product. For the first time, hexanol was produced directly from CO2:H2 blend, achieving the highest maximum productivity reported so far via gas fermentation. Traces of valerate, pentanol, eptanol and octanol were observed in the fermentation broth. The adapted strain shows promising to enrich the product spectrum targetable by future gas fermentation processes.
Collapse
Affiliation(s)
- G Antonicelli
- Centre for Sustainable Future Technologies, Fondazione Istituto Italiano di Tecnologia, Via Livorno 60, 10144 Turin, Italy; Department of Environment, Land and Infrastructure Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy
| | - L Ricci
- Centre for Sustainable Future Technologies, Fondazione Istituto Italiano di Tecnologia, Via Livorno 60, 10144 Turin, Italy
| | - L Tarraran
- Centre for Sustainable Future Technologies, Fondazione Istituto Italiano di Tecnologia, Via Livorno 60, 10144 Turin, Italy; Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy
| | - S Fraterrigo Garofalo
- Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy
| | - A Re
- Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy
| | - N S Vasile
- Centre for Sustainable Future Technologies, Fondazione Istituto Italiano di Tecnologia, Via Livorno 60, 10144 Turin, Italy; Department of Environment, Land and Infrastructure Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy
| | - F Verga
- Department of Environment, Land and Infrastructure Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy
| | - C F Pirri
- Centre for Sustainable Future Technologies, Fondazione Istituto Italiano di Tecnologia, Via Livorno 60, 10144 Turin, Italy; Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy
| | - B Menin
- Centre for Sustainable Future Technologies, Fondazione Istituto Italiano di Tecnologia, Via Livorno 60, 10144 Turin, Italy; Istituto di Biologia e Biotecnologia Agraria, Consiglio Nazionale delle Ricerche, Via Alfonso Corti 12, 20133 Milan, Italy
| | - V Agostino
- Centre for Sustainable Future Technologies, Fondazione Istituto Italiano di Tecnologia, Via Livorno 60, 10144 Turin, Italy.
| |
Collapse
|
9
|
Fuchs W, Rachbauer L, Rittmann SKMR, Bochmann G, Ribitsch D, Steger F. Eight Up-Coming Biotech Tools to Combat Climate Crisis. Microorganisms 2023; 11:1514. [PMID: 37375016 DOI: 10.3390/microorganisms11061514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 06/02/2023] [Accepted: 06/05/2023] [Indexed: 06/29/2023] Open
Abstract
Biotechnology has a high potential to substantially contribute to a low-carbon society. Several green processes are already well established, utilizing the unique capacity of living cells or their instruments. Beyond that, the authors believe that there are new biotechnological procedures in the pipeline which have the momentum to add to this ongoing change in our economy. Eight promising biotechnology tools were selected by the authors as potentially impactful game changers: (i) the Wood-Ljungdahl pathway, (ii) carbonic anhydrase, (iii) cutinase, (iv) methanogens, (v) electro-microbiology, (vi) hydrogenase, (vii) cellulosome and, (viii) nitrogenase. Some of them are fairly new and are explored predominantly in science labs. Others have been around for decades, however, with new scientific groundwork that may rigorously expand their roles. In the current paper, the authors summarize the latest state of research on these eight selected tools and the status of their practical implementation. We bring forward our arguments on why we consider these processes real game changers.
Collapse
Affiliation(s)
- Werner Fuchs
- Department IFA-Tulln, Institute of Environmental Biotechnology, University of Natural Resources and Life Sciences, Vienna, Konrad-Lorenz-Strasse 20, 3430 Tulln, Austria
| | - Lydia Rachbauer
- Lawrence Berkeley National Laboratory, Deconstruction Division at the Joint Bioenergy Institute, 5885 Hollis Street, Emeryville, CA 94608, USA
| | - Simon K-M R Rittmann
- Archaea Physiology & Biotechnology Group, Department of Functional and Evolutionary Ecology, Universität Wien, Djerassiplatz 1, 1030 Wien, Austria
| | - Günther Bochmann
- Department IFA-Tulln, Institute of Environmental Biotechnology, University of Natural Resources and Life Sciences, Vienna, Konrad-Lorenz-Strasse 20, 3430 Tulln, Austria
| | - Doris Ribitsch
- ACIB-Austrian Centre of Industrial Biotechnology, Krenngasse 37, 8010 Graz, Austria
| | - Franziska Steger
- Department IFA-Tulln, Institute of Environmental Biotechnology, University of Natural Resources and Life Sciences, Vienna, Konrad-Lorenz-Strasse 20, 3430 Tulln, Austria
| |
Collapse
|
10
|
Wood JC, Gonzalez-Garcia RA, Daygon D, Talbo G, Plan MR, Marcellin E, Virdis B. Characterisation of acetogen formatotrophic potential using Eubacterium limosum. Appl Microbiol Biotechnol 2023:10.1007/s00253-023-12600-6. [PMID: 37272938 DOI: 10.1007/s00253-023-12600-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 05/09/2023] [Accepted: 05/14/2023] [Indexed: 06/06/2023]
Abstract
Formate is a promising energy carrier that could be used to transport renewable electricity. Some acetogenic bacteria, such as Eubacterium limosum, have the native ability to utilise formate as a sole substrate for growth, which has sparked interest in the biotechnology industry. However, formatotrophic metabolism in E. limosum is poorly understood, and a system-level characterisation in continuous cultures is yet to be reported. Here, we present the first steady-state dataset for E. limosum formatotrophic growth. At a defined dilution rate of 0.4 d-1, there was a high specific uptake rate of formate (280 ± 56 mmol/gDCW/d; gDCW = gramme dry cell weight); however, most carbon went to CO2 (150 ± 11 mmol/gDCW/d). Compared to methylotrophic growth, protein differential expression data and intracellular metabolomics revealed several key features of formate metabolism. Upregulation of phosphotransacetylase (Pta) appears to be a futile attempt of cells to produce acetate as the major product. Instead, a cellular energy limitation resulted in the accumulation of intracellular pyruvate and upregulation of pyruvate formate ligase (Pfl) to convert formate to pyruvate. Therefore, metabolism is controlled, at least partially, at the protein expression level, an unusual feature for an acetogen. We anticipate that formate could be an important one-carbon substrate for acetogens to produce chemicals rich in pyruvate, a metabolite generally in low abundance during syngas growth. KEY POINTS: First Eubacterium limosum steady-state formatotrophic growth omics dataset High formate specific uptake rate, however carbon dioxide was the major product Formate may be the cause of intracellular stress and biofilm formation.
Collapse
Affiliation(s)
- Jamin C Wood
- Australian Centre for Water and Environmental Biotechnology (ACWEB), The University of Queensland, QLD, Brisbane, 4072, Australia
| | - R Axayacatl Gonzalez-Garcia
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, QLD, Brisbane, 4072, Australia
| | - Dara Daygon
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, QLD, Brisbane, 4072, Australia
- Metabolomics Australia (Queensland Node), The University of Queensland, QLD, Brisbane, 4072, Australia
| | - Gert Talbo
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, QLD, Brisbane, 4072, Australia
- Metabolomics Australia (Queensland Node), The University of Queensland, QLD, Brisbane, 4072, Australia
| | - Manuel R Plan
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, QLD, Brisbane, 4072, Australia
- Metabolomics Australia (Queensland Node), The University of Queensland, QLD, Brisbane, 4072, Australia
| | - Esteban Marcellin
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, QLD, Brisbane, 4072, Australia
- Metabolomics Australia (Queensland Node), The University of Queensland, QLD, Brisbane, 4072, Australia
| | - Bernardino Virdis
- Australian Centre for Water and Environmental Biotechnology (ACWEB), The University of Queensland, QLD, Brisbane, 4072, Australia.
| |
Collapse
|
11
|
Olivier A, Desgagnés A, Mercier E, Iliuta MC. New Insights on Catalytic Valorization of Carbon Dioxide by Conventional and Intensified Processes. Ind Eng Chem Res 2023. [DOI: 10.1021/acs.iecr.3c00064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
Affiliation(s)
- Antoine Olivier
- Department of Chemical Engineering, Laval University, Québec, G1 V 0A6, Canada
| | - Alex Desgagnés
- Department of Chemical Engineering, Laval University, Québec, G1 V 0A6, Canada
| | - Etienne Mercier
- Department of Chemical Engineering, Laval University, Québec, G1 V 0A6, Canada
| | - Maria C. Iliuta
- Department of Chemical Engineering, Laval University, Québec, G1 V 0A6, Canada
| |
Collapse
|
12
|
Allaart MT, Diender M, Sousa DZ, Kleerebezem R. Overflow metabolism at the thermodynamic limit of life: How carboxydotrophic acetogens mitigate carbon monoxide toxicity. Microb Biotechnol 2023; 16:697-705. [PMID: 36632026 PMCID: PMC10034630 DOI: 10.1111/1751-7915.14212] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 11/29/2022] [Accepted: 01/01/2023] [Indexed: 01/13/2023] Open
Abstract
Carboxydotrophic metabolism is gaining interest due to its applications in gas fermentation technology, enabling the conversion of carbon monoxide to fuels and commodities. Acetogenic carboxydotrophs play a central role in current gas fermentation processes. In contrast to other energy-rich microbial substrates, CO is highly toxic, which makes it a challenging substrate to utilize. Instantaneous scavenging of CO upon entering the cell is required to mitigate its toxicity. Experiments conducted with Clostridium autoethanogenum at different biomass-specific growth rates show that elevated ethanol production occurs at increasing growth rates. The increased allocation of electrons towards ethanol at higher growth rates strongly suggests that C. autoethanogenum employs a form of overflow metabolism to cope with high dissolved CO concentrations. We argue that this overflow branch enables acetogens to efficiently use CO at highly variable substrate influxes by increasing the conversion rate almost instantaneously when required to remove toxic substrate and promote growth. In this perspective, we will address the case study of C. autoethanogenum grown solely on CO and syngas mixtures to assess how it employs acetate reduction to ethanol as a form of overflow metabolism.
Collapse
Affiliation(s)
| | - Martijn Diender
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Diana Z Sousa
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| |
Collapse
|
13
|
Philp J. Bioeconomy and net-zero carbon: lessons from Trends in Biotechnology, volume 1, issue 1. Trends Biotechnol 2023; 41:307-322. [PMID: 36272819 DOI: 10.1016/j.tibtech.2022.09.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 09/15/2022] [Accepted: 09/23/2022] [Indexed: 11/06/2022]
Abstract
Many biotechnology applications tend to be for low production volumes and relatively high-value products such as insulin and vaccines. More difficult to perfect at scale are bioprocesses for high-volume products with lower value, especially if the target product is a reduced chemical such as a solvent or a plastic. Historically, industrial microbiology succeeded under special circumstances when fossil feedstocks were either unavailable or expensive. Inevitably, as these circumstances relaxed, bioprocesses struggled to compete with petrochemistry. Why try to compete? Fossil resources will be phased out in the coming decades in the struggle with climate change. To reach net-zero carbon by 2050 will require all sectors to transition, not only energy and transportation. This may herald a new opportunity for industrial bioprocesses with much better tools.
Collapse
Affiliation(s)
- Jim Philp
- Organization for Economic Cooperation and Development (OECD), Paris, France.
| |
Collapse
|
14
|
Ceron-Chafla P, de Vrieze J, Rabaey K, van Lier JB, Lindeboom REF. Steering the product spectrum in high-pressure anaerobic processes: CO 2 partial pressure as a novel tool in biorefinery concepts. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:27. [PMID: 36803622 PMCID: PMC9938588 DOI: 10.1186/s13068-023-02262-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 01/05/2023] [Indexed: 02/19/2023]
Abstract
BACKGROUND Elevated CO2 partial pressure (pCO2) has been proposed as a potential steering parameter for selective carboxylate production in mixed culture fermentation. It is anticipated that intermediate product spectrum and production rates, as well as changes in the microbial community, are (in)directly influenced by elevated pCO2. However, it remains unclear how pCO2 interacts with other operational conditions, namely substrate specificity, substrate-to-biomass (S/X) ratio and the presence of an additional electron donor, and what effect pCO2 has on the exact composition of fermentation products. Here, we investigated possible steering effects of elevated pCO2 combined with (1) mixed substrate (glycerol/glucose) provision; (2) subsequent increments in substrate concentration to increase the S/X ratio; and (3) formate as an additional electron donor. RESULTS Metabolite predominance, e.g., propionate vs. butyrate/acetate, and cell density, depended on interaction effects between pCO2-S/X ratio and pCO2-formate. Individual substrate consumption rates were negatively impacted by the interaction effect between pCO2-S/X ratio and were not re-established after lowering the S/X ratio and adding formate. The product spectrum was influenced by the microbial community composition, which in turn, was modified by substrate type and the interaction effect between pCO2-formate. High propionate and butyrate levels strongly correlated with Negativicutes and Clostridia predominance, respectively. After subsequent pressurized fermentation phases, the interaction effect between pCO2-formate enabled a shift from propionate towards succinate production when mixed substrate was provided. CONCLUSIONS Overall, interaction effects between elevated pCO2, substrate specificity, high S/X ratio and availability of reducing equivalents from formate, rather than an isolated pCO2 effect, modified the proportionality of propionate, butyrate and acetate in pressurized mixed substrate fermentations at the expense of reduced consumption rates and increased lag-phases. The interaction effect between elevated pCO2 and formate was beneficial for succinate production and biomass growth with a glycerol/glucose mixture as the substrate. The positive effect may be attributed to the availability of extra reducing equivalents, likely enhanced carbon fixating activity and hindered propionate conversion due to increased concentration of undissociated carboxylic acids.
Collapse
Affiliation(s)
- Pamela Ceron-Chafla
- Sanitary Engineering Section, Department of Water Management, Delft University of Technology, Stevinweg 1, 2628 CN, Delft, The Netherlands.
| | - Jo de Vrieze
- grid.5342.00000 0001 2069 7798Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - Korneel Rabaey
- grid.5342.00000 0001 2069 7798Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000 Ghent, Belgium ,grid.510907.aCenter for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Coupure Links 653, 9000 Ghent, Belgium
| | - Jules B. van Lier
- grid.5292.c0000 0001 2097 4740Sanitary Engineering Section, Department of Water Management, Delft University of Technology, Stevinweg 1, 2628 CN Delft, The Netherlands
| | - Ralph E. F. Lindeboom
- grid.5292.c0000 0001 2097 4740Sanitary Engineering Section, Department of Water Management, Delft University of Technology, Stevinweg 1, 2628 CN Delft, The Netherlands
| |
Collapse
|
15
|
Winkelhorst M, Cabau-Peinado O, Straathof AJ, Jourdin L. Biomass-specific rates as key performance indicators: A nitrogen balancing method for biofilm-based electrochemical conversion. Front Bioeng Biotechnol 2023; 11:1096086. [PMID: 36741763 PMCID: PMC9892193 DOI: 10.3389/fbioe.2023.1096086] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 01/04/2023] [Indexed: 01/20/2023] Open
Abstract
Microbial electrochemical technologies (METs) employ microorganisms utilizing solid-state electrodes as either electron sink or electron source, such as in microbial electrosynthesis (MES). METs reaction rate is traditionally normalized to the electrode dimensions or to the electrolyte volume, but should also be normalized to biomass amount present in the system at any given time. In biofilm-based systems, a major challenge is to determine the biomass amount in a non-destructive manner, especially in systems operated in continuous mode and using 3D electrodes. We developed a simple method using a nitrogen balance and optical density to determine the amount of microorganisms in biofilm and in suspension at any given time. For four MES reactors converting CO2 to carboxylates, >99% of the biomass was present as biofilm after 69 days of reactor operation. After a lag phase, the biomass-specific growth rate had increased to 0.12-0.16 days-1. After 100 days of operation, growth became insignificant. Biomass-specific production rates of carboxylates varied between 0.08-0.37 molC molX -1d-1. Using biomass-specific rates, one can more effectively assess the performance of MES, identify its limitations, and compare it to other fermentation technologies.
Collapse
|
16
|
Kwon SJ, Lee J, Lee HS. Metabolic changes of the acetogen Clostridium sp. AWRP through adaptation to acetate challenge. Front Microbiol 2022; 13:982442. [PMID: 36569090 PMCID: PMC9768041 DOI: 10.3389/fmicb.2022.982442] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 11/14/2022] [Indexed: 12/12/2022] Open
Abstract
In this study, we report the phenotypic changes that occurred in the acetogenic bacterium Clostridium sp. AWRP as a result of an adaptive laboratory evolution (ALE) under the acetate challenge. Acetate-adapted strain 46 T-a displayed acetate tolerance to acetate up to 10 g L-1 and increased ethanol production in small-scale cultures. The adapted strain showed a higher cell density than AWRP even without exogenous acetate supplementation. 46 T-a was shown to have reduced gas consumption rate and metabolite production. It was intriguing to note that 46 T-a, unlike AWRP, continued to consume H2 at low CO2 levels. Genome sequencing revealed that the adapted strain harbored three point mutations in the genes encoding an electron-bifurcating hydrogenase (Hyt) crucial for autotrophic growth in CO2 + H2, in addition to one in the dnaK gene. Transcriptome analysis revealed that most genes involved in the CO2-fixation Wood-Ljungdahl pathway and auxiliary pathways for energy conservation (e.g., Rnf complex, Nfn, etc.) were significantly down-regulated in 46 T-a. Several metabolic pathways involved in dissimilation of nucleosides and carbohydrates were significantly up-regulated in 46 T-a, indicating that 46 T-a evolved to utilize organic substrates rather than CO2 + H2. Further investigation into degeneration in carbon fixation of the acetate-adapted strain will provide practical implications for CO2 + H2 fermentation using acetogenic bacteria for long-term continuous fermentation.
Collapse
Affiliation(s)
- Soo Jae Kwon
- Marine Biotechnology Research Center, Korea Institute of Ocean Science and Technology, Busan, South Korea,Department of Marine Biotechnology, University of Science and Technology, Daejeon, South Korea
| | - Joungmin Lee
- Marine Biotechnology Research Center, Korea Institute of Ocean Science and Technology, Busan, South Korea,*Correspondence: Joungmin Lee,
| | - Hyun Sook Lee
- Marine Biotechnology Research Center, Korea Institute of Ocean Science and Technology, Busan, South Korea,Department of Marine Biotechnology, University of Science and Technology, Daejeon, South Korea,Hyun Sook Lee,
| |
Collapse
|
17
|
Ricci L, Seifert A, Bernacchi S, Fino D, Pirri CF, Re A. Leveraging substrate flexibility and product selectivity of acetogens in two-stage systems for chemical production. Microb Biotechnol 2022; 16:218-237. [PMID: 36464980 PMCID: PMC9871533 DOI: 10.1111/1751-7915.14172] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 10/31/2022] [Accepted: 11/08/2022] [Indexed: 12/09/2022] Open
Abstract
Carbon dioxide (CO2 ) stands out as sustainable feedstock for developing a circular carbon economy whose energy supply could be obtained by boosting the production of clean hydrogen from renewable electricity. H2 -dependent CO2 gas fermentation using acetogenic microorganisms offers a viable solution of increasingly demonstrated value. While gas fermentation advances to achieve commercial process scalability, which is currently limited to a few products such as acetate and ethanol, it is worth taking the best of the current state-of-the-art technology by its integration within innovative bioconversion schemes. This review presents multiple scenarios where gas fermentation by acetogens integrate into double-stage biotechnological production processes that use CO2 as sole carbon feedstock and H2 as energy carrier for products' synthesis. In the integration schemes here reviewed, the first stage can be biotic or abiotic while the second stage is biotic. When the first stage is biotic, acetogens act as a biological platform to generate chemical intermediates such as acetate, formate and ethanol that become substrates for a second fermentation stage. This approach holds the potential to enhance process titre/rate/yield metrics and products' spectrum. Alternatively, when the first stage is abiotic, the integrated two-stage scheme foresees, in the first stage, the catalytic transformation of CO2 into C1 products that, in the second stage, can be metabolized by acetogens. This latter scheme leverages the metabolic flexibility of acetogens in efficient utilization of the products of CO2 abiotic hydrogenation, namely formate and methanol, to synthesize multicarbon compounds but also to act as flexible catalysts for hydrogen storage or production.
Collapse
Affiliation(s)
- Luca Ricci
- Department of Applied Science and TechnologyPolitecnico di TorinoTurinItaly,Centre for Sustainable Future TechnologiesFondazione Istituto Italiano di TecnologiaTurinItaly
| | | | | | - Debora Fino
- Department of Applied Science and TechnologyPolitecnico di TorinoTurinItaly,Centre for Sustainable Future TechnologiesFondazione Istituto Italiano di TecnologiaTurinItaly
| | - Candido Fabrizio Pirri
- Department of Applied Science and TechnologyPolitecnico di TorinoTurinItaly,Centre for Sustainable Future TechnologiesFondazione Istituto Italiano di TecnologiaTurinItaly
| | - Angela Re
- Department of Applied Science and TechnologyPolitecnico di TorinoTurinItaly,Centre for Sustainable Future TechnologiesFondazione Istituto Italiano di TecnologiaTurinItaly
| |
Collapse
|
18
|
Conversion of Syngas from Entrained Flow Gasification of Biogenic Residues with Clostridium carboxidivorans and Clostridium autoethanogenum. FERMENTATION 2022. [DOI: 10.3390/fermentation8090465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Synthesis gas fermentation is a microbial process, which uses anaerobic bacteria to convert CO-rich gases to organic acids and alcohols and thus presents a promising technology for the sustainable production of fuels and platform chemicals from renewable sources. Clostridium carboxidivorans and Clostridium autoethanogenum are two acetogenic bacteria, which have shown their high potential for these processes by their high tolerance toward CO and in the production of industrially relevant products such as ethanol, 1-butanol, 1-hexanol, and 2,3-butanediol. A promising approach is the coupling of gasification of biogenic residues with a syngas fermentation process. This study investigated batch processes with C. carboxidivorans and C. autoethanogenum in fully controlled stirred-tank bioreactors and continuous gassing with biogenic syngas produced by an autothermal entrained flow gasifier on a pilot scale >1200 °C. They were then compared to the results of artificial gas mixtures of pure gases. Because the biogenic syngas contained 2459 ppm O2 from the bottling process after gasification of torrefied wood and subsequent syngas cleaning for reducing CH4, NH3, H2S, NOX, and HCN concentrations, the oxygen in the syngas was reduced to 259 ppm O2 with a Pd catalyst before entering the bioreactor. The batch process performance of C. carboxidivorans in a stirred-tank bioreactor with continuous gassing of purified biogenic syngas was identical to an artificial syngas mixture of the pure gases CO, CO2, H2, and N2 within the estimation error. The alcohol production by C. autoethanogenum was even improved with the purified biogenic syngas compared to reference batch processes with the corresponding artificial syngas mixture. Both acetogens have proven their potential for successful fermentation processes with biogenic syngas, but full carbon conversion to ethanol is challenging with the investigated biogenic syngas.
Collapse
|
19
|
Benito-Vaquerizo S, Parera Olm I, de Vroet T, Schaap PJ, Sousa DZ, Martins Dos Santos VAP, Suarez-Diez M. Genome-scale metabolic modelling enables deciphering ethanol metabolism via the acrylate pathway in the propionate-producer Anaerotignum neopropionicum. Microb Cell Fact 2022; 21:116. [PMID: 35710409 PMCID: PMC9205015 DOI: 10.1186/s12934-022-01841-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 05/26/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Microbial production of propionate from diluted streams of ethanol (e.g., deriving from syngas fermentation) is a sustainable alternative to the petrochemical production route. Yet, few ethanol-fermenting propionigenic bacteria are known, and understanding of their metabolism is limited. Anaerotignum neopropionicum is a propionate-producing bacterium that uses the acrylate pathway to ferment ethanol and CO2 to propionate and acetate. In this work, we used computational and experimental methods to study the metabolism of A. neopropionicum and, in particular, the pathway for conversion of ethanol into propionate. RESULTS Our work describes iANEO_SB607, the first genome-scale metabolic model (GEM) of A. neopropionicum. The model was built combining the use of automatic tools with an extensive manual curation process, and it was validated with experimental data from this and published studies. The model predicted growth of A. neopropionicum on ethanol, lactate, sugars and amino acids, matching observed phenotypes. In addition, the model was used to implement a dynamic flux balance analysis (dFBA) approach that accurately predicted the fermentation profile of A. neopropionicum during batch growth on ethanol. A systematic analysis of the metabolism of A. neopropionicum combined with model simulations shed light into the mechanism of ethanol fermentation via the acrylate pathway, and revealed the presence of the electron-transferring complexes NADH-dependent reduced ferredoxin:NADP+ oxidoreductase (Nfn) and acryloyl-CoA reductase-EtfAB, identified for the first time in this bacterium. CONCLUSIONS The realisation of the GEM iANEO_SB607 is a stepping stone towards the understanding of the metabolism of the propionate-producer A. neopropionicum. With it, we have gained insight into the functioning of the acrylate pathway and energetic aspects of the cell, with focus on the fermentation of ethanol. Overall, this study provides a basis to further exploit the potential of propionigenic bacteria as microbial cell factories.
Collapse
Affiliation(s)
- Sara Benito-Vaquerizo
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, Wageningen, 6708WE, The Netherlands
| | - Ivette Parera Olm
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, Wageningen, 6708WE, The Netherlands
| | - Thijs de Vroet
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, Wageningen, 6708WE, The Netherlands
| | - Peter J Schaap
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, Wageningen, 6708WE, The Netherlands
| | - Diana Z Sousa
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, Wageningen, 6708WE, The Netherlands.,Centre for Living Technologies, Alliance TU/e, WUR, UU, UMC Utrecht, Vening Meinesz building C, Princetonlaan 6, Utrecht, 3584 CB, The Netherlands
| | - Vitor A P Martins Dos Santos
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, Wageningen, 6708WE, The Netherlands.,Bioprocess Engineering, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
| | - Maria Suarez-Diez
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, Wageningen, 6708WE, The Netherlands.
| |
Collapse
|
20
|
Cell-free prototyping enables implementation of optimized reverse β-oxidation pathways in heterotrophic and autotrophic bacteria. Nat Commun 2022; 13:3058. [PMID: 35650184 PMCID: PMC9160091 DOI: 10.1038/s41467-022-30571-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Accepted: 05/09/2022] [Indexed: 11/12/2022] Open
Abstract
Carbon-negative synthesis of biochemical products has the potential to mitigate global CO2 emissions. An attractive route to do this is the reverse β-oxidation (r-BOX) pathway coupled to the Wood-Ljungdahl pathway. Here, we optimize and implement r-BOX for the synthesis of C4-C6 acids and alcohols. With a high-throughput in vitro prototyping workflow, we screen 762 unique pathway combinations using cell-free extracts tailored for r-BOX to identify enzyme sets for enhanced product selectivity. Implementation of these pathways into Escherichia coli generates designer strains for the selective production of butanoic acid (4.9 ± 0.1 gL−1), as well as hexanoic acid (3.06 ± 0.03 gL−1) and 1-hexanol (1.0 ± 0.1 gL−1) at the best performance reported to date in this bacterium. We also generate Clostridium autoethanogenum strains able to produce 1-hexanol from syngas, achieving a titer of 0.26 gL−1 in a 1.5 L continuous fermentation. Our strategy enables optimization of r-BOX derived products for biomanufacturing and industrial biotechnology. An attractive route for carbon-negative synthesis of biochemical products is the reverse β-oxidation pathway coupled to the Wood-Ljungdahl pathway. Here the authors use a high-throughput in vitro prototyping workflow to screen 762 unique pathway combinations using cell-free extracts tailored for r-BOX to identify enzyme sets for enhanced product selectivity.
Collapse
|
21
|
Stikane A, Dace E, Stalidzans E. Closing the loop in bioproduction: Spent Microbial Biomass as a resource within circular bioeconomy. N Biotechnol 2022; 70:109-115. [DOI: 10.1016/j.nbt.2022.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 04/15/2022] [Accepted: 06/03/2022] [Indexed: 11/30/2022]
|
22
|
Puiman L, Elisiário MP, Crasborn LM, Wagenaar LE, Straathof AJ, Haringa C. Gas mass transfer in syngas fermentation broths is enhanced by ethanol. Biochem Eng J 2022. [DOI: 10.1016/j.bej.2022.108505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
|
23
|
Recycling carbon for sustainable protein production using gas fermentation. Curr Opin Biotechnol 2022; 76:102723. [PMID: 35487158 DOI: 10.1016/j.copbio.2022.102723] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 02/23/2022] [Accepted: 03/17/2022] [Indexed: 02/07/2023]
Abstract
Current food production practices contribute significantly to climate change. To transition into a sustainable future, a combination of new food habits and a radical food production innovation must occur. Single-cell protein from microbial fermentation can profoundly impact sustainability. This review paper explores opportunities offered by gas fermentation to completely replace our reliance on fossil fuels for the production of food. Together with synthetic biology, designed microbial proteins from gas fermentation have the potential to reduce our dependence on fossil fuels and make food production more sustainable.
Collapse
|
24
|
de Lima LA, Ingelman H, Brahmbhatt K, Reinmets K, Barry C, Harris A, Marcellin E, Köpke M, Valgepea K. Faster Growth Enhances Low Carbon Fuel and Chemical Production Through Gas Fermentation. Front Bioeng Biotechnol 2022; 10:879578. [PMID: 35497340 PMCID: PMC9039284 DOI: 10.3389/fbioe.2022.879578] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 03/14/2022] [Indexed: 12/13/2022] Open
Abstract
Gas fermentation offers both fossil carbon-free sustainable production of fuels and chemicals and recycling of gaseous and solid waste using gas-fermenting microbes. Bioprocess development, systems-level analysis of biocatalyst metabolism, and engineering of cell factories are advancing the widespread deployment of the commercialised technology. Acetogens are particularly attractive biocatalysts but effects of the key physiological parameter–specific growth rate (μ)—on acetogen metabolism and the gas fermentation bioprocess have not been established yet. Here, we investigate the μ-dependent bioprocess performance of the model-acetogen Clostridium autoethanogenum in CO and syngas (CO + CO2+H2) grown chemostat cultures and assess systems-level metabolic responses using gas analysis, metabolomics, transcriptomics, and metabolic modelling. We were able to obtain steady-states up to μ ∼2.8 day−1 (∼0.12 h−1) and show that faster growth supports both higher yields and productivities for reduced by-products ethanol and 2,3-butanediol. Transcriptomics data revealed differential expression of 1,337 genes with increasing μ and suggest that C. autoethanogenum uses transcriptional regulation to a large extent for facilitating faster growth. Metabolic modelling showed significantly increased fluxes for faster growing cells that were, however, not accompanied by gene expression changes in key catabolic pathways for CO and H2 metabolism. Cells thus seem to maintain sufficient “baseline” gene expression to rapidly respond to CO and H2 availability without delays to kick-start metabolism. Our work advances understanding of transcriptional regulation in acetogens and shows that faster growth of the biocatalyst improves the gas fermentation bioprocess.
Collapse
Affiliation(s)
- Lorena Azevedo de Lima
- ERA Chair in Gas Fermentation Technologies, Institute of Technology, University of Tartu, Tartu, Estonia
| | - Henri Ingelman
- ERA Chair in Gas Fermentation Technologies, Institute of Technology, University of Tartu, Tartu, Estonia
| | - Kush Brahmbhatt
- ERA Chair in Gas Fermentation Technologies, Institute of Technology, University of Tartu, Tartu, Estonia
| | - Kristina Reinmets
- ERA Chair in Gas Fermentation Technologies, Institute of Technology, University of Tartu, Tartu, Estonia
| | - Craig Barry
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, St. Lucia, QLD, Australia
| | | | - Esteban Marcellin
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, St. Lucia, QLD, Australia
| | | | - Kaspar Valgepea
- ERA Chair in Gas Fermentation Technologies, Institute of Technology, University of Tartu, Tartu, Estonia
- *Correspondence: Kaspar Valgepea,
| |
Collapse
|
25
|
Hu L, Guo S, Wang B, Fu R, Fan D, Jiang M, Fei Q, Gonzalez R. Bio-valorization of C1 gaseous substrates into bioalcohols: Potentials and challenges in reducing carbon emissions. Biotechnol Adv 2022; 59:107954. [DOI: 10.1016/j.biotechadv.2022.107954] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 03/29/2022] [Accepted: 04/04/2022] [Indexed: 11/02/2022]
|
26
|
Turning waste gases into valuables. Synth Syst Biotechnol 2022; 7:847-848. [PMID: 35572765 PMCID: PMC9079231 DOI: 10.1016/j.synbio.2022.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
|
27
|
Oliveira L, Rückel A, Nordgauer L, Schlumprecht P, Hutter E, Weuster-Botz D. Comparison of Syngas-Fermenting Clostridia in Stirred-Tank Bioreactors and the Effects of Varying Syngas Impurities. Microorganisms 2022; 10:microorganisms10040681. [PMID: 35456733 PMCID: PMC9032146 DOI: 10.3390/microorganisms10040681] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 03/17/2022] [Accepted: 03/18/2022] [Indexed: 11/24/2022] Open
Abstract
In recent years, syngas fermentation has emerged as a promising means for the production of fuels and platform chemicals, with a variety of acetogens efficiently converting CO-rich gases to ethanol. However, the feasibility of syngas fermentation processes is related to the occurrence of syngas impurities such as NH3, H2S, and NOX. Therefore, the effects of defined additions of NH4+, H2S, and NO3− were studied in autotrophic batch processes with C. autoethanogenum, C. ljungdahlii, and C. ragsdalei while applying continuously gassed stirred-tank bioreactors. Any initial addition of ammonium and nitrate curbed the cell growth of the Clostridia being studied and reduced the final alcohol concentrations. C. ljungdahlii showed the highest tolerance to ammonium and nitrate, whereas C. ragsdalei was even positively influenced by the presence of 0.1 g L−1 H2S. Quantitative goals for the purification of syngas were identified for each of the acetogens studied in the used experimental setup. Syngas purification should in particular focus on the NOX impurities that caused the highest inhibiting effect and maintain the concentrations of NH3 and H2S within an acceptable range (e.g., NH3 < 4560 ppm and H2S < 108 ppm) in order to avoid inhibition through the accumulation of these impurities in the bioreactor.
Collapse
|
28
|
Heffernan JK, Mahamkali V, Valgepea K, Marcellin E, Nielsen LK. Analytical tools for unravelling the metabolism of gas-fermenting Clostridia. Curr Opin Biotechnol 2022; 75:102700. [PMID: 35240422 DOI: 10.1016/j.copbio.2022.102700] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 01/24/2022] [Accepted: 02/05/2022] [Indexed: 12/23/2022]
Abstract
Acetogens harness the Wood-Ljungdahl Pathway, a unique metabolic pathway for C1 capture close to the thermodynamic limit. Gas fermentation using acetogens is already used for CO-to-ethanol conversion at industrial-scale and has the potential to valorise a range of C1 and waste substrates to short-chain and medium-chain carboxylic acids and alcohols. Advances in analytical quantification and metabolic modelling have helped guide industrial gas fermentation designs. Further advances in the measurements of difficult to measure metabolites are required to improve kinetic modelling and understand the regulation of acetogen metabolism. This will help guide future synthetic biology designs needed to realise the full potential of gas fermentation in stimulating a circular bioeconomy.
Collapse
Affiliation(s)
- James K Heffernan
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Vishnu Mahamkali
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Kaspar Valgepea
- ERA Chair in Gas Fermentation Technologies, Institute of Technology, University of Tartu, Tartu 50411, Estonia
| | - Esteban Marcellin
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia; Queensland Node of Metabolomics Australia, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Lars K Nielsen
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia; Queensland Node of Metabolomics Australia, The University of Queensland, Brisbane, QLD 4072, Australia; The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark.
| |
Collapse
|
29
|
|
30
|
Biosynthesis of butyrate from methanol and carbon monoxide by recombinant Acetobacterium woodii. Int Microbiol 2022; 25:551-560. [PMID: 35179672 PMCID: PMC9307552 DOI: 10.1007/s10123-022-00234-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 12/21/2021] [Accepted: 01/11/2022] [Indexed: 10/27/2022]
Abstract
Methanol is one of the most widely produced organic substrates from syngas and can serve as a bio-feedstock to cultivate acetogenic bacteria which allows a major contribution to reducing greenhouse gas. Acetobacterium woodii is one of the very few acetogens that can utilize methanol to produce acetate as sole product. Since A. woodii is genetically tractable, it is an interesting candidate to introduce recombinant pathways for production of bio-commodities from methanol. In this study, we introduced the butyrate production operon from a related acetogen, Eubacterium callanderi KIST612, into A. woodii and show a stable production of butyrate from methanol. This study also reveals how butyrate production by recombinant A. woodii strains can be enhanced with addition of electrons in the form of carbon monoxide. Our results not only show a stable expression system of non-native enzymes in A. woodii but also increase in the product spectrum of A. woodii to compounds with higher economic value.
Collapse
|
31
|
Pavan M, Reinmets K, Garg S, Mueller AP, Marcellin E, Köpke M, Valgepea K. Advances in systems metabolic engineering of autotrophic carbon oxide-fixing biocatalysts towards a circular economy. Metab Eng 2022; 71:117-141. [DOI: 10.1016/j.ymben.2022.01.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 01/24/2022] [Accepted: 01/25/2022] [Indexed: 12/16/2022]
|
32
|
Ntagia E, Chatzigiannidou I, Carvajal-Arroyo JM, Arends JBA, Rabaey K. Continuous H 2/CO 2 fermentation for acetic acid production under transient and continuous sulfide inhibition. CHEMOSPHERE 2021; 285:131536. [PMID: 34273695 DOI: 10.1016/j.chemosphere.2021.131536] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 07/08/2021] [Accepted: 07/09/2021] [Indexed: 06/13/2023]
Abstract
Waste gas fermentation powered by renewable H2 is reaching kiloton scale. The presence of sulfide, inherent to many waste gases, can cause inhibition, requiring additional gas treatment. In this work, acetogenesis and methanogenesis inhibition by sulfide were studied in a 10-L mixed-culture fermenter, supplied with CO2 and connected with a water electrolysis unit for electricity-powered H2 supply. Three cycles of inhibition (1.3 mM total dissolved sulfide (TDS)) and recovery were applied, then the fermenter was operated at 0.5 mM TDS for 35 days. During operation at 0.5 mM TDS the acetate production rate reached 7.1 ± 1.5 mmol C L-1 d-1. Furthermore, 43.7 ± 15.6% of the electrons, provided as H2, were distributed to acetate and 7.7 ± 4.1% to butyrate, the second most abundant fermentation product. Selectivity of sulfide as inhibitor was demonstrated by a 7 days lag-phase of methanogenesis recovery, compared to 48 h for acetogenesis and by the less than 1% electrons distribution to CH4, under 0.5 mM TDS. The microbial community was dominated by Eubacterium, Proteiniphilum and an unclassified member of the Eggerthellaceae family. The taxonomic diversity of the community decreased and conversely the phenotypic diversity increased, during operation. This work illustrated the scale-up potential of waste gas fermentations, by elucidating the effect of sulfide as a common gas impurity, and by demonstrating continuous, potentially renewable supply of electrons.
Collapse
Affiliation(s)
- Eleftheria Ntagia
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000, Gent, Belgium; CAPTURE, www.capture-resources.be, Belgium
| | - Ioanna Chatzigiannidou
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000, Gent, Belgium
| | - Jose M Carvajal-Arroyo
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000, Gent, Belgium
| | - Jan B A Arends
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000, Gent, Belgium; CAPTURE, www.capture-resources.be, Belgium
| | - Korneel Rabaey
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000, Gent, Belgium; CAPTURE, www.capture-resources.be, Belgium.
| |
Collapse
|
33
|
Wood JC, Marcellin E, Plan MR, Virdis B. High methanol-to-formate ratios induce butanol production in Eubacterium limosum. Microb Biotechnol 2021; 15:1542-1549. [PMID: 34841673 PMCID: PMC9049608 DOI: 10.1111/1751-7915.13963] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 10/06/2021] [Accepted: 10/20/2021] [Indexed: 11/29/2022] Open
Abstract
Unlike gaseous C1 feedstocks for acetogenic bacteria, there has been less attention on liquid C1 feedstocks, despite benefits in terms of energy efficiency, mass transfer and integration within existing fermentation infrastructure. Here, we present growth of Eubacterium limosum ATCC8486 using methanol and formate as substrates, finding evidence for the first time of native butanol production. We varied ratios of methanol‐to‐formate in batch serum bottle fermentations, showing butyrate is the major product (maximum specific rate 220 ± 23 mmol‐C gDCW‐1day‐1). Increasing this ratio showed methanol is the key feedstock driving the product spectrum towards more reduced products, such as butanol (maximum titre 2.0 ± 1.1 mM‐C). However, both substrates are required for a high growth rate (maximum 0.19 ± 0.011 h‐1) and cell density (maximum 1.2 ± 0.043 gDCW l‐1), with formate being the preferred substrate. In fact, formate and methanol are consumed in two distinct growth phases – growth phase 1, on predominately formate and growth phase 2 on methanol, which must balance. Because the second growth varied according to the first growth on formate, this suggests butanol production is due to overflow metabolism, similar to 2,3‐butanediol production in other acetogens. However, further research is required to confirm the butanol production pathway in E. limosum, particularly given, unlike other substrates, methanol likely results in mostly NADH generation, not reduced ferredoxin.
Collapse
Affiliation(s)
- Jamin C Wood
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, Brisbane, Qld, 4072, Australia
| | - Esteban Marcellin
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Qld, 4072, Australia.,Metabolomics Australia (Queensland node), The University of Queensland, Brisbane, Qld, 4072, Australia
| | - Manuel R Plan
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Qld, 4072, Australia.,Metabolomics Australia (Queensland node), The University of Queensland, Brisbane, Qld, 4072, Australia
| | - Bernardino Virdis
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, Brisbane, Qld, 4072, Australia
| |
Collapse
|
34
|
Screening of Gas Substrate and Medium Effects on 2,3-Butanediol Production with C. ljungdahlii and C. autoethanogenum Aided by Improved Autotrophic Cultivation Technique. FERMENTATION 2021. [DOI: 10.3390/fermentation7040264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Gas fermentation by acetogens of the genus Clostridium is an attractive technology since it affords the production of biochemicals and biofuels from industrial waste gases while contributing to mitigate the carbon cycle alterations. The acetogenic model organisms C. ljungdahlii and C. autoethanogenum have already been used in large scale industrial fermentations. Among the natural products, ethanol production has already attained industrial scale. However, some acetogens are also natural producers of 2,3-butanediol (2,3-BDO), a platform chemical of relevant industrial interest. Here, we have developed a lab-scale screening campaign with the aim of enhancing 2,3-BDO production. Our study generated comparable data on growth and 2,3-BDO production of several batch gas fermentations using C. ljungdahlii and C. autoethanogenum grown on different gas substrates of primary applicative interest (CO2 · H2, CO · CO2, syngas) and on different media featuring different compositions as regards trace metals, mineral elements and vitamins. CO · CO2 fermentation was found to be preferable for the production of 2,3-BDO, and a fair comparison of the strains cultivated in comparable conditions revealed that C. ljungdahlii produced 3.43-fold higher titer of 2,3-BDO compared to C. autoethanogenum. Screening of different medium compositions revealed that mineral elements, Zinc and Iron exert a major positive influence on 2,3-BDO titer and productivity. Moreover, the CO2 influence on CO fermentation was explored by characterizing C. ljungdahlii response with respect to different gas ratios in the CO · CO2 gas mixtures. The screening strategies undertaken in this study led to the production of 2.03 ± 0.05 g/L of 2,3-BDO, which is unprecedented in serum bottle experiments.
Collapse
|
35
|
Litty D, Müller V. Butyrate production in the acetogen Eubacterium limosum is dependent on the carbon and energy source. Microb Biotechnol 2021; 14:2686-2692. [PMID: 33629808 PMCID: PMC8601167 DOI: 10.1111/1751-7915.13779] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 02/09/2021] [Accepted: 02/09/2021] [Indexed: 11/29/2022] Open
Abstract
Eubacterium limosum KIST612 is one of the few acetogenic bacteria that has the genes encoding for butyrate synthesis from acetyl-CoA, and indeed, E. limosum KIST612 is known to produce butyrate from CO but not from H2 + CO2 . Butyrate production from CO was only seen in bioreactors with cell recycling or in batch cultures with addition of acetate. Here, we present detailed study on growth of E. limosum KIST612 on different carbon and energy sources with the goal, to find other substrates that lead to butyrate formation. Batch fermentations in serum bottles revealed that acetate was the major product under all conditions investigated. Butyrate formation from the C1 compounds carbon dioxide and hydrogen, carbon monoxide or formate was not observed. However, growth on glucose led to butyrate formation, but only in the stationary growth phase. A maximum of 4.3 mM butyrate was observed, corresponding to a butyrate:glucose ratio of 0.21:1 and a butyrate:acetate ratio of 0.14:1. Interestingly, growth on the C1 substrate methanol also led to butyrate formation in the stationary growth phase with a butyrate:methanol ratio of 0.17:1 and a butyrate:acetate ratio of 0.33:1. Since methanol can be produced chemically from carbon dioxide, this offers the possibility for a combined chemical-biochemical production of butyrate from H2 + CO2 using this acetogenic biocatalyst. With the advent of genetic methods in acetogens, butanol production from methanol maybe possible as well.
Collapse
Affiliation(s)
- Dennis Litty
- Department of Molecular Microbiology & BioenergeticsInstitute of Molecular BiosciencesGoethe‐University Frankfurt am MainHessenGermany
| | - Volker Müller
- Department of Molecular Microbiology & BioenergeticsInstitute of Molecular BiosciencesGoethe‐University Frankfurt am MainHessenGermany
| |
Collapse
|
36
|
Butelmann T, Priks H, Parent Z, Johnston TG, Tamm T, Nelson A, Lahtvee PJ, Kumar R. Metabolism Control in 3D-Printed Living Materials Improves Fermentation. ACS APPLIED BIO MATERIALS 2021; 4:7195-7203. [PMID: 35006951 DOI: 10.1021/acsabm.1c00754] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The three-dimensional (3D) printing of cell-containing polymeric hydrogels creates living materials (LMs), offering a platform for developing innovative technologies in areas like biosensors and biomanufacturing. The polymer material properties of cross-linkable F127-bis-urethane methacrylate (F127-BUM) allow reproducible 3D printing and stability in physiological conditions, making it suitable for fabricating LMs. Though F127-BUM-based LMs permit diffusion of solute molecules like glucose and ethanol, it remains unknown whether these are permissible for oxygen, essential for respiration. To determine oxygen permissibility, we quantified dissolved oxygen consumption by the budding yeast-laden F127-BUM-based LMs. Moreover, we obtained data on cell-retaining LMs, which allowed a direct comparison between LMs and suspension cultures. We further developed a highly reliable method to isolate cells from LMs for flow cytometry analysis, cell viability evaluation, and the purification of macromolecules. We found oxygen consumption heavily impaired inside LMs, indicating that yeast metabolism relies primarily on fermentation instead of respiration. Applying this finding to brewing, we observed a higher (3.7%) ethanol production using LMs than the traditional brewing process, indicating improved fermentation. Our study concludes that the present F127-BUM-based LMs are useful for microaerobic processes but developing aerobic bioprocesses will require further research.
Collapse
Affiliation(s)
- Tobias Butelmann
- Institute of Technology, University of Tartu, 50411 Tartu, Estonia.,Institute for Macromolecular Chemistry, University of Freiburg, 79104 Freiburg, Germany
| | - Hans Priks
- Institute of Technology, University of Tartu, 50411 Tartu, Estonia
| | - Zoel Parent
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Trevor G Johnston
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Tarmo Tamm
- Institute of Technology, University of Tartu, 50411 Tartu, Estonia
| | - Alshakim Nelson
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Petri-Jaan Lahtvee
- Institute of Technology, University of Tartu, 50411 Tartu, Estonia.,Department of Chemistry and Biotechnology, Tallinn University of Technology, 12618 Tallinn, Estonia
| | - Rahul Kumar
- Institute of Technology, University of Tartu, 50411 Tartu, Estonia.,Department of Chemistry and Biotechnology, Tallinn University of Technology, 12618 Tallinn, Estonia
| |
Collapse
|
37
|
Wood JC, Grové J, Marcellin E, Heffernan JK, Hu S, Yuan Z, Virdis B. Strategies to improve viability of a circular carbon bioeconomy-A techno-economic review of microbial electrosynthesis and gas fermentation. WATER RESEARCH 2021; 201:117306. [PMID: 34153823 DOI: 10.1016/j.watres.2021.117306] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 04/30/2021] [Accepted: 05/24/2021] [Indexed: 06/13/2023]
Abstract
A circular carbon bioeconomy has potential to halt atmospheric accumulation of greenhouse gases causing climate change and sustainably produce chemical, agricultural and fuel products. Here, we report application of a simplified technoeconomic assessment to critically review two approaches in this space - microbial electrosynthesis and gas fermentation. For microbial electrosynthesis, decoupling of surface-dependant abiotic process for electron delivery from volume-dependant biotic carbon fixation, is shown as the only economically viable strategy to scale-up due to comparatively low biofilm electron consumption rate. This is effectively an electrolyser-assisted gas fermentation system. Targeting high-value products, such as protein for human food consumption is one of the few pathways forward for electrolyser-assisted gas fermentation. Alternatively, gas fermentation of reformed biogas presents an interesting and potentially more sustainable implementation pathway to improve economic viability of chemicals. This critical review suggests linking water treatment resource recovery with gas fermentation is attractive for bioplastics and butanol in terms of competitiveness and market demand.
Collapse
Affiliation(s)
- Jamin C Wood
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Johannes Grové
- Energy & Poverty Group, School of Chemical Engineering, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Esteban Marcellin
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia; Queensland Node of Metabolomics Australia, The University of Queensland, Brisbane, QLD 4072, Australia
| | - James K Heffernan
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Shihu Hu
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Zhiguo Yuan
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Bernardino Virdis
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD 4072, Australia.
| |
Collapse
|
38
|
Lai CY, Zhou L, Yuan Z, Guo J. Hydrogen-driven microbial biogas upgrading: Advances, challenges and solutions. WATER RESEARCH 2021; 197:117120. [PMID: 33862393 DOI: 10.1016/j.watres.2021.117120] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 03/12/2021] [Accepted: 04/02/2021] [Indexed: 06/12/2023]
Abstract
As a clean and renewable energy, biogas is an important alternative to fossil fuels. However, the high carbon dioxide (CO2) content in biogas limits its value as a fuel. 'Biogas upgrading' is an advanced process which removes CO2 from biogas, thereby converting biogas to biomethane, which has a higher commercial value. Microbial technologies offer a sustainable and cost-effective way to upgrade biogas, removing CO2 using hydrogen (H2) as electron donor, generated by surplus electricity from renewable wind or solar energy. Hydrogenotrophic methanogens can be applied to convert CO2 with H2 to methane (CH4), or alternatively, homoacetogens can convert both CO2 and H2 into value-added chemicals. Here, we comprehensively review the current state of biogas generation and utilization, and describe the advances in biological, H2-dependent biogas upgrading technologies, with particular attention to key challenges associated with the processes, e.g., metabolic limitations, low H2 transfer rate, and finite CO2 conversion rate. We also highlight several new strategies for overcoming technical barriers to achieve efficient CO2 conversion, including process optimization to eliminate metabolic limitation, novel reactor designs to improve H2 transfer rate and utilization efficiency, and employing advanced genetic engineering tools to generate more efficient microorganisms. The insights offered in this review will promote further exploration into microbial, H2-driven biogas upgrading, towards addressing the global energy crisis and climate change associated with use of fossil fuels.
Collapse
Affiliation(s)
- Chun-Yu Lai
- Advanced Water Management Centre, The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia
| | - Linjie Zhou
- Advanced Water Management Centre, The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia
| | - Zhiguo Yuan
- Advanced Water Management Centre, The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia
| | - Jianhua Guo
- Advanced Water Management Centre, The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia.
| |
Collapse
|
39
|
Hermann M, Teleki A, Weitz S, Niess A, Freund A, Bengelsdorf FR, Dürre P, Takors R. Identifying and Engineering Bottlenecks of Autotrophic Isobutanol Formation in Recombinant C. ljungdahlii by Systemic Analysis. Front Bioeng Biotechnol 2021; 9:647853. [PMID: 33748092 PMCID: PMC7968104 DOI: 10.3389/fbioe.2021.647853] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 02/09/2021] [Indexed: 11/13/2022] Open
Abstract
Clostridium ljungdahlii (C. ljungdahlii, CLJU) is natively endowed producing acetic acid, 2,3-butandiol, and ethanol consuming gas mixtures of CO2, CO, and H2 (syngas). Here, we present the syngas-based isobutanol formation using C. ljungdahlii harboring the recombinant amplification of the "Ehrlich" pathway that converts intracellular KIV to isobutanol. Autotrophic isobutanol production was studied analyzing two different strains in 3-L gassed and stirred bioreactors. Physiological characterization was thoroughly applied together with metabolic profiling and flux balance analysis. Thereof, KIV and pyruvate supply were identified as key "bottlenecking" precursors limiting preliminary isobutanol formation in CLJU[KAIA] to 0.02 g L-1. Additional blocking of valine synthesis in CLJU[KAIA]:ilvE increased isobutanol production by factor 6.5 finally reaching 0.13 g L-1. Future metabolic engineering should focus on debottlenecking NADPH availability, whereas NADH supply is already equilibrated in the current generation of strains.
Collapse
Affiliation(s)
- Maria Hermann
- Institute of Biochemical Engineering, Faculty of Energy-, Process-, and Bio-Engineering, University of Stuttgart, Stuttgart, Germany
| | - Attila Teleki
- Institute of Biochemical Engineering, Faculty of Energy-, Process-, and Bio-Engineering, University of Stuttgart, Stuttgart, Germany
| | - Sandra Weitz
- Institute of Microbiology and Biotechnology, Faculty of Natural Sciences, University of Ulm, Ulm, Germany
| | - Alexander Niess
- Institute of Biochemical Engineering, Faculty of Energy-, Process-, and Bio-Engineering, University of Stuttgart, Stuttgart, Germany
| | - Andreas Freund
- Institute of Biochemical Engineering, Faculty of Energy-, Process-, and Bio-Engineering, University of Stuttgart, Stuttgart, Germany
| | - Frank Robert Bengelsdorf
- Institute of Microbiology and Biotechnology, Faculty of Natural Sciences, University of Ulm, Ulm, Germany
| | - Peter Dürre
- Institute of Microbiology and Biotechnology, Faculty of Natural Sciences, University of Ulm, Ulm, Germany
| | - Ralf Takors
- Institute of Biochemical Engineering, Faculty of Energy-, Process-, and Bio-Engineering, University of Stuttgart, Stuttgart, Germany
| |
Collapse
|
40
|
Novak K, Neuendorf CS, Kofler I, Kieberger N, Klamt S, Pflügl S. Blending industrial blast furnace gas with H 2 enables Acetobacterium woodii to efficiently co-utilize CO, CO 2 and H 2. BIORESOURCE TECHNOLOGY 2021; 323:124573. [PMID: 33360948 DOI: 10.1016/j.biortech.2020.124573] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 12/14/2020] [Accepted: 12/15/2020] [Indexed: 06/12/2023]
Abstract
In this study, the impact of gas composition (i.e. CO, CO2 and H2 partial pressures) on CO2 utilization, growth, and acetate production was investigated in batch and continuous cultures of A. woodii. Based on an industrial blast furnace gas, H2 blending was used to study the impact of H2 availability on CO2 fixation alone and together with CO using idealized gas streams. With H2 available as an additional energy source, net CO2 fixation and CO, CO2 and H2 co-utilization was achieved in gas-limited fermentations. Using industrial blast furnace gas, up to 15.1 g l-1 acetate were produced in continuous cultures. Flux balance analysis showed that intracellular fluxes and total ATP production were dependent on the availability of H2 and CO. Overall, H2 blending was shown to be a suitable control strategy for gas fermentations and demonstrated that A. woodii is an interesting host for CO2 fixation from industrial gas streams.
Collapse
Affiliation(s)
- Katharina Novak
- Technische Universität Wien, Institute for Chemical, Environmental and Bioscience Engineering, Research Area Biochemical Engineering, Gumpendorfer Straße 1a, 1060 Vienna, Austria.
| | - Christian Simon Neuendorf
- Technische Universität Wien, Institute for Chemical, Environmental and Bioscience Engineering, Research Area Biochemical Engineering, Gumpendorfer Straße 1a, 1060 Vienna, Austria.
| | | | - Nina Kieberger
- voestalpine Stahl GmbH, voestalpine-Straße 3, 4020 Linz, Austria.
| | - Steffen Klamt
- Max Planck Institute for Dynamics of Complex Technical Systems, 39106 Magdeburg, Germany.
| | - Stefan Pflügl
- Technische Universität Wien, Institute for Chemical, Environmental and Bioscience Engineering, Research Area Biochemical Engineering, Gumpendorfer Straße 1a, 1060 Vienna, Austria.
| |
Collapse
|
41
|
Syngas Derived from Lignocellulosic Biomass Gasification as an Alternative Resource for Innovative Bioprocesses. Processes (Basel) 2020. [DOI: 10.3390/pr8121567] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A hybrid system based on lignocellulosic biomass gasification and syngas fermentation represents a second-generation biorefinery approach that is currently in the development phase. Lignocellulosic biomass can be gasified to produce syngas, which is a gas mixture consisting mainly of H2, CO, and CO2. The major challenge of biomass gasification is the syngas’s final quality. Consequently, the development of effective syngas clean-up technologies has gained increased interest in recent years. Furthermore, the bioconversion of syngas components has been intensively studied using acetogenic bacteria and their Wood–Ljungdahl pathway to produce, among others, acetate, ethanol, butyrate, butanol, caproate, hexanol, 2,3-butanediol, and lactate. Nowadays, syngas fermentation appears to be a promising alternative for producing commodity chemicals in comparison to fossil-based processes. Research studies on syngas fermentation have been focused on process design and optimization, investigating the medium composition, operating parameters, and bioreactor design. Moreover, metabolic engineering efforts have been made to develop genetically modified strains with improved production. In 2018, for the first time, a syngas fermentation pilot plant from biomass gasification was built by LanzaTech Inc. in cooperation with Aemetis, Inc. Future research will focus on coupling syngas fermentation with additional bioprocesses and/or on identifying new non-acetogenic microorganisms to produce high-value chemicals beyond acetate and ethanol.
Collapse
|
42
|
Hermann M, Teleki A, Weitz S, Niess A, Freund A, Bengelsdorf FR, Takors R. Electron availability in CO 2 , CO and H 2 mixtures constrains flux distribution, energy management and product formation in Clostridium ljungdahlii. Microb Biotechnol 2020; 13:1831-1846. [PMID: 32691533 PMCID: PMC7533319 DOI: 10.1111/1751-7915.13625] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 06/14/2020] [Accepted: 06/24/2020] [Indexed: 01/25/2023] Open
Abstract
Acetogens such as Clostridium ljungdahlii can play a crucial role reducing the human CO2 footprint by converting industrial emissions containing CO2 , CO and H2 into valuable products such as organic acids or alcohols. The quantitative understanding of cellular metabolism is a prerequisite to exploit the bacterial endowments and to fine-tune the cells by applying metabolic engineering tools. Studying the three gas mixtures CO2 + H2 , CO and CO + CO2 + H2 (syngas) by continuously gassed batch cultivation experiments and applying flux balance analysis, we identified CO as the preferred carbon and electron source for growth and producing alcohols. However, the total yield of moles of carbon (mol-C) per electrons consumed was almost identical in all setups which underlines electron availability as the main factor influencing product formation. The Wood-Ljungdahl pathway (WLP) showed high flexibility by serving as the key NAD+ provider for CO2 + H2, whereas this function was strongly compensated by the transhydrogenase-like Nfn complex when CO was metabolized. Availability of reduced ferredoxin (Fdred ) can be considered as a key determinant of metabolic control. Oxidation of CO via carbon monoxide dehydrogenase (CODH) is the main route of Fdred formation when CO is used as substrate, whereas Fdred is mainly regenerated via the methyl branch of WLP and the Nfn complex utilizing CO2 + H2 . Consequently, doubled growth rates, highest ATP formation rates and highest amounts of reduced products (ethanol, 2,3-butanediol) were observed when CO was the sole carbon and electron source.
Collapse
Affiliation(s)
- Maria Hermann
- Institute of Biochemical EngineeringUniversity of StuttgartAllmandring 31Stuttgart70569Germany
| | - Attila Teleki
- Institute of Biochemical EngineeringUniversity of StuttgartAllmandring 31Stuttgart70569Germany
| | - Sandra Weitz
- Institute of Microbiology and BiotechnologyUlm UniversityAlbert‐Einstein‐Allee 11Ulm89069Germany
| | - Alexander Niess
- Institute of Biochemical EngineeringUniversity of StuttgartAllmandring 31Stuttgart70569Germany
| | - Andreas Freund
- Institute of Biochemical EngineeringUniversity of StuttgartAllmandring 31Stuttgart70569Germany
| | - Frank R. Bengelsdorf
- Institute of Microbiology and BiotechnologyUlm UniversityAlbert‐Einstein‐Allee 11Ulm89069Germany
| | - Ralf Takors
- Institute of Biochemical EngineeringUniversity of StuttgartAllmandring 31Stuttgart70569Germany
| |
Collapse
|
43
|
Walls LE, Rios-Solis L. Sustainable Production of Microbial Isoprenoid Derived Advanced Biojet Fuels Using Different Generation Feedstocks: A Review. Front Bioeng Biotechnol 2020; 8:599560. [PMID: 33195174 PMCID: PMC7661957 DOI: 10.3389/fbioe.2020.599560] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 10/09/2020] [Indexed: 01/17/2023] Open
Abstract
As the fastest mode of transport, the aircraft is a major driver for globalization and economic growth. The development of alternative advanced liquid fuels is critical to sustainable development within the sector. Such fuels should be compatible with existing infrastructure and derived from second generation feedstocks to avoid competition with food markets. With properties similar to petroleum based fuels, isoprenoid derived compounds such as limonene, bisabolane, farnesane, and pinene dimers are of increasing interest as "drop-in" replacement jet fuels. In this review potential isoprenoid derived jet fuels and progress toward their microbial production was discussed in detail. Although substantial advancements have been achieved, the use of first generation feedstocks remains ubiquitous. Lignocellulosic biomass is the most abundant raw material available for biofuel production, however, technological constraints associated with its pretreatment and saccharification hinder its economic feasibility for low-value commodity production. Non-conventional microbes with novel characteristics including cellulolytic bacteria and fungi capable of highly efficient lignocellulose degradation and xylose fermenting oleaginous yeast with enhanced lignin-associated inhibitor tolerance were investigated as alternatives to traditional model hosts. Finally, innovative bioprocessing methods including consolidated bioprocessing and sequential bioreactor approaches, with potential to capitalize on such unique natural capabilities were considered.
Collapse
Affiliation(s)
- Laura Ellen Walls
- Institute for Bioengineering, School of Engineering, The University of Edinburgh, Edinburgh, United Kingdom
- Centre for Synthetic and Systems Biology (SynthSys), The University of Edinburgh, Edinburgh, United Kingdom
| | - Leonardo Rios-Solis
- Institute for Bioengineering, School of Engineering, The University of Edinburgh, Edinburgh, United Kingdom
- Centre for Synthetic and Systems Biology (SynthSys), The University of Edinburgh, Edinburgh, United Kingdom
| |
Collapse
|
44
|
Lemaire ON, Wagner T. Gas channel rerouting in a primordial enzyme: Structural insights of the carbon-monoxide dehydrogenase/acetyl-CoA synthase complex from the acetogen Clostridium autoethanogenum. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1862:148330. [PMID: 33080205 DOI: 10.1016/j.bbabio.2020.148330] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 10/01/2020] [Accepted: 10/15/2020] [Indexed: 10/23/2022]
Abstract
Clostridium autoethanogenum, the bacterial model for biological conversion of waste gases into biofuels, grows under extreme carbon-monoxide (CO) concentrations. The strictly anaerobic bacterium derives its entire cellular energy and carbon from this poisonous gas, therefore requiring efficient molecular machineries for CO-conversion. Here, we structurally and biochemically characterized the key enzyme of the CO-converting metabolism: the CO-dehydrogenase/Acetyl-CoA synthase (CODH/ACS). We obtained crystal structures of natively isolated complexes from fructose-grown and CO-grown C. autoethanogenum cultures. Both contain the same isoforms and if the overall structure adopts the classic α2β2 architecture, comparable to the model enzyme from Moorella thermoacetica, the ACS binds a different position on the CODH core. The structural characterization of a proteolyzed complex and the conservation of the binding interface in close homologs rejected the possibility of a crystallization artefact. Therefore, the internal CO-channeling system, critical to transfer CO generated at the C-cluster to the ACS active site, drastically differs in the complex from C. autoethanogenum. The 1.9-Å structure of the CODH alone provides an accurate picture of the new CO-routes, leading to the ACS core and reaching the surface. Increased gas accessibility would allow the simultaneous CO-oxidation and acetyl-CoA production. Biochemical experiments showed higher flexibility of the ACS subunit from C. autoethanogenum compared to M. thermoacetica, albeit monitoring similar CO-oxidation and formation rates. These results show a reshuffling of internal CO-tunnels during evolution of these Firmicutes, putatively leading to a bidirectional complex that ensure a high flux of CO-conversion toward energy conservation, acting as the main cellular powerplant.
Collapse
Affiliation(s)
- Olivier N Lemaire
- Max Planck Institute for Marine Microbiology, Celsiusstraße 1, 28359 Bremen, Germany
| | - Tristan Wagner
- Max Planck Institute for Marine Microbiology, Celsiusstraße 1, 28359 Bremen, Germany.
| |
Collapse
|
45
|
Synthetic Biology on Acetogenic Bacteria for Highly Efficient Conversion of C1 Gases to Biochemicals. Int J Mol Sci 2020; 21:ijms21207639. [PMID: 33076477 PMCID: PMC7589590 DOI: 10.3390/ijms21207639] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/13/2020] [Accepted: 10/13/2020] [Indexed: 12/13/2022] Open
Abstract
Synthesis gas, which is mainly produced from fossil fuels or biomass gasification, consists of C1 gases such as carbon monoxide, carbon dioxide, and methane as well as hydrogen. Acetogenic bacteria (acetogens) have emerged as an alternative solution to recycle C1 gases by converting them into value-added biochemicals using the Wood-Ljungdahl pathway. Despite the advantage of utilizing acetogens as biocatalysts, it is difficult to develop industrial-scale bioprocesses because of their slow growth rates and low productivities. To solve these problems, conventional approaches to metabolic engineering have been applied; however, there are several limitations owing to the lack of required genetic bioparts for regulating their metabolic pathways. Recently, synthetic biology based on genetic parts, modules, and circuit design has been actively exploited to overcome the limitations in acetogen engineering. This review covers synthetic biology applications to design and build industrial platform acetogens.
Collapse
|
46
|
Vees CA, Neuendorf CS, Pflügl S. Towards continuous industrial bioprocessing with solventogenic and acetogenic clostridia: challenges, progress and perspectives. J Ind Microbiol Biotechnol 2020; 47:753-787. [PMID: 32894379 PMCID: PMC7658081 DOI: 10.1007/s10295-020-02296-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 07/20/2020] [Indexed: 12/11/2022]
Abstract
The sustainable production of solvents from above ground carbon is highly desired. Several clostridia naturally produce solvents and use a variety of renewable and waste-derived substrates such as lignocellulosic biomass and gas mixtures containing H2/CO2 or CO. To enable economically viable production of solvents and biofuels such as ethanol and butanol, the high productivity of continuous bioprocesses is needed. While the first industrial-scale gas fermentation facility operates continuously, the acetone-butanol-ethanol (ABE) fermentation is traditionally operated in batch mode. This review highlights the benefits of continuous bioprocessing for solvent production and underlines the progress made towards its establishment. Based on metabolic capabilities of solvent producing clostridia, we discuss recent advances in systems-level understanding and genome engineering. On the process side, we focus on innovative fermentation methods and integrated product recovery to overcome the limitations of the classical one-stage chemostat and give an overview of the current industrial bioproduction of solvents.
Collapse
Affiliation(s)
- Charlotte Anne Vees
- Institute of Chemical, Environmental and Bioscience Engineering, Research Area Biochemical Engineering, Technische Universität Wien, Gumpendorfer Straße 1a, 1060 Vienna, Austria
| | - Christian Simon Neuendorf
- Institute of Chemical, Environmental and Bioscience Engineering, Research Area Biochemical Engineering, Technische Universität Wien, Gumpendorfer Straße 1a, 1060 Vienna, Austria
| | - Stefan Pflügl
- Institute of Chemical, Environmental and Bioscience Engineering, Research Area Biochemical Engineering, Technische Universität Wien, Gumpendorfer Straße 1a, 1060 Vienna, Austria
| |
Collapse
|
47
|
Affiliation(s)
- Bernhard Hauer
- Institute of Biochemistry and Technical Biochemistry, Department of Technical Biochemistry, Universitaet Stuttgart, Allmandring 31, 70569 Stuttgart, Germany
| |
Collapse
|